1. Field of the Invention
The present invention relates generally to a forward/reverse clutchless transmission with a 1 to 1 forward drive ratio. More specifically, the invention relates to a planetary gear transmission with a synchro-meshing system which allows operation at moderate input shaft R.P.M. without the aid of a clutch.
2. Description of Related Art
Typical manual transmission systems utilize a clutch mechanism between the power source and the input shaft which disengages the power to the input shaft to allow the transmission to change gears without grinding the gears. Clutch mechanisms are relatively complex and expensive pieces of machinery and tend to require frequent maintenance due to slippage wear caused by continuous loading and unloading. The expense of a clutch mechanism for use in transmissions made for simple forward and reverse output tends to be cost prohibitive. The direct engagement between the internal gears that would result if a clutch mechanism was not used would wear on the internal gears due to grinding during engagement on the gears and therefore the gears would need to be stronger and larger to prevent their failure due to the wear. There is a need for a transmission which is simple in design and which combines the benefits of a planetary gear system with a synchro-mesh system.
U.S. Pat. No. 1,983,834, issued on Dec. 11, 1934, to William B. Barnes describes a planetary gear overdrive transmission adapted for association with the main transmission of an automobile whereby a supplemental speed change may be obtained. The patent to Barnes fails to describe the benefits of the present invention.
U.S. Pat. No. 2,582,487, issued on Jan. 15, 1952, to Donald W. Kelbel describes a planetary gear transmission which provides a plurality of speed ratios between the driving and the driven shafts and uses two clutches. U.S. Pat. No. 2,599,559, issued on Jun. 10, 1952, to Donald W. Kelbel describes a planetary gear transmission which is provides three forward speeds and a reverse speed and which uses an overrunning clutch. The clutch mechanisms used in the Kelbel patents make the designs more complex and expensive to maintain.
U.S. Pat. No. 2,910,893, issued on Nov. 3, 1959, to Lucien Peras describes a reversing device that incorporates planetary gears, an engagement sleeve, and a friction clutch to provide smooth forward and reverse switching. The patent to Peras describes a permanently actuated friction clutch between the driving and the driven shafts which results in a continuous loss of energy and increases the need to replace worn parts.
U.S. Pat. No. 3,478,622, issued on Nov. 18, 1969, to Larry R. Reid describes a marine planetary gear transmission which provides a forward direct driving relation by caging the planetary gears, the input sun gear, and the output ring gear by moving the planetary gear system longitudinally on the input shaft and bringing a further ring gear that is common to the planetary gears into engagement with the sun gear. Reverse drive is obtained by braking the caging member associated with the planetary gears while the further ring gear is disconnected from the sun gear. U.S. Pat. No. 3,529,494, issued on Sep. 22, 1970, to Gaston Matte describes a reversing gear assembly which uses a planetary gear system, a sun gear and a ring gear. Both the patent to Reid and the patent to Matte require the planetary carrier to move longitudinally on the input shaft and fail to describe any mechanism to provide a smooth and efficient shifting from neutral to forward.
U.S. Pat. No. 4,274,304, issued on Jun. 23, 1981, to George R. Curtiss describes an in-line reversing mechanism comprised of a planetary gearing assembly and a braking assembly for reverse operation. The reversing mechanism requires the use of sawtooth-like teeth which only engage in one rotational direction and several sets of epicyclic gear trains in order to facilitate the reversing mechanism.
U.S. Pat. No. 4,569,252, issued on Feb. 11, 1986, to Joseph F. B. Harper describes a planetary gear transmission using a planetary gearing system comprising a sun gear meshingly engaged with multiple planetary gears carried by a planetary carrier which planetary gears are in turn meshed with a ring gear and which includes a clutching means. The patent to Harper is complex in design. The patent to Harper uses a clutching means to shift from a neutral position to a reverse position. The use of a clutching means to accomplish a reverse rotation of the output shaft is unnecessary and will increase the cost to manufacture and maintain the transmission.
German Patent Number 2,339,253, published on Feb. 14, 1974, and PCT International Publication Number WO 86/07423, published on Dec. 18, 1986, describe reversing gear assemblies which use a planetary gear system, a sun gear and a ring gear. Both patent fail to describe any mechanism to provide a smooth and efficient shifting from neutral to forward.
Japanese Patent Application Publication Number 06323378(A), published on Nov. 25, 1994, describes a reversing gear assembly which use a planetary gear system, a sun gear, a ring gear, and a clutch mechanism. The Japanese patent application describes a transmission which is complex in design and requires the use of a clutch mechanism.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a hybrid transmission solving the aforementioned problems is desired.